1. Field of the Invention
This invention relates to a system for control of telephone and non-telephone equipment located on the premises of a telephone subscriber's residence or business, using standard telephone set apparatuses connected to a switched telephone network. More precisely, the system receives dual tone multi-frequency (DTMF) signals on the telephone lines, decodes and validates these signals and generates d.c. off/on control signals for activating or deactivating the subscriber's equipment connected to the system.
The DTMF signals may be generated locally, at the subscriber station, or from a remote location via the telephone wires that connect the subscriber's premises to the public switched telephone network.
2. Description of the Prior Art
Conventionally, in order to communicate a control command to an appliance, the user should personally actuate a desired command. The system of the present invention allows the user to control the appliances on his/her premises remotely, by use of a telephone which is connected to the switched telephone network.
As well, conventionally, for requesting a pay TV program, the user should establish telephone voice communication with the distribution center for ordering the program and for attending to various accounting matters. According to the present invention, the subscriber may control the delivery and selection of television delivered programming with ease. An example of a system for delivery and selection of TV programming by telephone is disclosed in U.S. Pat. No. 4,878,245 (Bradley et al.), where DTMF signals generate by the subscriber's telephone set are used to control equipment which is not located on the subscriber's premises.
The system of the present invention allows the user to control not only TV appliances, but also any type of telephone and non-telephone equipment. Thus, facsimile equipment at subscriber's premises may be operated through the telephone when the telephone line is busy (off-hook line) or idle (on-hook line), which is not taught by the prior art.
In contrast with the prior art, the system of the present invention incorporates means for reducing the interference between conventional telephone communication and the on-premises control functions.